Electric heater



March 31. 1925;

w. PENZOLD ELECTRIC HEATER Filed July 22, 1924- Jfz menial" Patented Mar. 3t, 1925.

outrun stares WILHELM PENZGLD, O'F HANOVER, G

, Mint, nssreuon ro winn asraunnnrran- GESELLSCHAFT Fll'R ELEKTEO-W'ARME-TECENEE, OE HANOVER, GERIlVi-I.t'kll'Y.v

ELECTRIC HEATER.

application filed. July 22,

To all whom it may concern:

Be it known that l, WILHELM PnNzoLn, a German subject, and residing at 15 Ruhmkorffstrasse, Hanover, Germany, have invented certain new and useful Improvements in Electric Heaters, of which the following is a specification.

This invention relates to electric heaters, and more particularly heaters for boiling water and the like orfor generating steam, and in which the heating current is led to the container by an electrode and passes through the fluid to another electrode or to the wall of the container which may act as an electrode. Several proposals have been made for regulating the resistance within the fluid to the'passage of the electric current, this result being obtained by regulating the area of the free cross section of liquid in the path by which the current passes from "one terminal to the other. Thus is has been proposed to insert the terminals inside a tubular body of insulating material and to alter the distance be tween the terminals thereby increasing the length of path of the current within the fluid. Another attempt at securing the desired end was to surround one of the electrodes with insulating bodies having various tortuous passages therein. Such insulating bodies have been made up of separate discs with poppets or feet formed thereon holding the discs at a desired distance apart so that narrow horizontal paths were formed for the passage of the current, the paths being adjustable by altering the "dis tance between the discs. The feet on which the discs rested were also formed to cut out part of the free cross section between neighbouring discs. The discs described were formed as rings surrounding the electrode.

The insulating bodies used in electric boilers are made of ceramic material, usually porcelain, and for this reason all complicated shapes are to be avoided on account of the difiiculties of production and the local stresses which may arise during operation and which lead to breakages. For these reasons any hollow or tubular formation is to be avoided, as breakages in the case of a tubular insulating body invariably mean a complete break down of the boiler. The discs mentioned above have not the dranbacks of a tubular construction, but have the 1924. Serial No. ?27,569.

serious disadvantage that the ring formation tends to distortion and the feet introduced a complication which rendered replacement of a disc somewhat costly.

According to this invention the insulating members are of simple form without any complication which could lead to inequality of strains or stresses when in operation and the adjustment of the free passage through the fluid is effected by arranging a plurality of the insulating bodies around an electrode so as to leave elongated vertical openings for the free passage of the current through the fluid, this free passage being adjustable by moving the bodies so as to make the spaces between them narrower. The bodies are conveniently formed by superposing a plurality of discs. A convenient arrangement is to employ four sets of superposed discs strung on carriers which may be moved radially outwards from the electrode to increase the openings between, or inwards to decrease these openings. By interposine fixed or separately adjustable bodies thh outward movement may effect a restriction in the free passage and a consequent in crease in the resistance to the current.

he invention is illustrated by way ofexample in the accompanying drawings in I which Fig. 1 is a partial vertical section of a heater according to this invention, and

1g. 2 is a plan of the same.

in carrying the invention into effect according to the form shown one of the electrodes is formed by the wall a of the heater and the central electrode 6 is suitably supported to hang downwards into the fluid to be heated. The central electrode is surrounded by four insulating bodies 0, which in the form shown are made up of a plurality of superposed discs, which are pro vided with holes by means of which they are strung on to a rod 05 so as to hold them in the form of a cylinder. The discs are supported on a platform a fixed by the flange e to the walls a of the heater and provided with openings 0 and e for enabling the circulation of the fluid. The upper ends of the rods cl are provided with heads and pass through radial slots 7' in a cross shaped piece f, situated over the electrode b. It will be understood that corresponding slots to the slots f are formed in the platform where the ends of the rods (Z pass through. By moving the bodies radially outward from the position shown in Figure 2, the width the elongated vertical spaces formed between the bodies 0 is altered, that is to say the dimension 9 marked in the figure increases. It will be evident that in this way the area ot the free pz ssage for the current is increased and the resistance thereby reduced, so that the heating action will be less. It now a second set of bodies is arranged between the electrodes, the path of the current is further broken up and a greater limit of control rendered possible. This result may be obtained by interposing bodi s sim lar to the bodies (1', but located a interii'icdiate points, that is to say on intermediate radii. l t hen two such sets are provided and each set contains four n'ien'ibers, as illustrated, the elongated passage g is split into two narrower elongated passages g g and the outward movement of the insulating bodies 0, will increase the area of the elongated slots g but will decrease the area ot' the passages 5/ The discs may be of any desired shape and thickness, but it is usually preferred to make them circular as shown. Also the size and shape of the inner and outer bodies 0 and 0 respectively may be altered as desired but for the sake of simplicity and ease of manufacture it is preferred to make them ot the same shapes and dimensions as shown. The porcelain rods (Z and the discs may be reinforced in any suitable and known manner it desired.

hen in use the improved form of electric heater may be set to give the required heating effect, by setting the bodies 0 radially in their guide slots f and as a rule no further adjustment will be necessary. The heating action is of course greatest at the point where the resistance is greatest, that is to say, at the point of least cross section of the tree passage in the fluid. This will be at the points indicated by the reference letters 9 and 9 It Will be at these points that scale tends to form most rapidly. The elongated form of the openings enables the scale to fall down to the bottom where it does not interfere with the continued operation of the ,ore

M lid tical passages between said bodies movable radially towards or away li. central electrode.

i. An electric heater comprising a lluid container torn'iing one electrode, a central electrode, a plurality of insulating bodies spaced synunetrically about said central elec trode and arranged to leave elongated rertical passages between and radial guide pieces for said bodies to guide their movement tow rds away from the central electrode.

t. An electric heater comprising a fluid container forming one electrode, a central electrode dipping into the fluid to be heated, insulating bodies composed of a plin'ality of superposed discs ant. spaced relatively to leave elongated vertical. openings for the pastsage 01 current from the central electrode to the outer electrode, said superposed discs being movable radially towards or away from said central electrode.

An electric heater comprising a ll iid container acting as one electrode, a central electrode, radial adjustable set oit elongated insulating bodies spaced so as to leave narrow vertical passages between and fixed insulating bodies arranged intermediate said adjustable bodies.

lVlLHELM PENZOLD.

Witnesses:

l/VLED Sunnn, H. P. JnssEN. 

